Why do Americans speak in such a vulgar manner? I'm not even talking about the niggers and rednecks.

It seems like all of them speak like they're mentally retarded and incapable of civilised speech. Is it "cool" over there?

"ayyo mane"
"wassup"
"he be in the attic"
"daaaaamn"
"shieeet"
"thots bro"
"i done that shit last week"
"i been there negro"
"i is 'gonna drop that fuckin' fag"

This is coming from an Australian, sort your vernacular out, otherwise I'll continue to regard you as the subhumans you are.